针对片上网络的低功耗互连设计

发布时间：2018-08-26 18:08

【摘要】：片上网络(NoC)是一种用于多处理器片上系统(MPSoC)的新型通信方法。该技术采用基于网络通讯的系统架构,不仅提高了通信效率,而且改善了可扩展性。同时,片上网络的引入有效地解决了传统的总线式SoC中出现的全局同步、带宽受限和功耗等问题。然而,随着集成电路工艺地逐步发展,特别是进入深亚微米工艺以后,NoC中互连结构引起的串扰等非理想效应带来了功耗、延时和可靠性等一系列问题。因此如何设计高速低功耗的NoC互连结构成为片上网络设计研究的热点之一。针对NoC中互连的功耗问题,提出了一种新型具有抑制串扰能力的低功耗编码——AGM。该编码的低功耗部分采用在低功耗自校准编码(SCG)的基础上改进得到的GM编码。同时,为了提高编码抑制串扰的能力引入时间编码技术。该编码的编解码器结构中还加入了并串/串并转换电路,通过减少互连线数量的方式降低互连功耗和节约布线资源。仿真结果表明,对于32bit随机数据源,AGM编码将互连线功耗降低了37.51%。为了进一步降低NoC的互连功耗,采用低功耗编码与低摆幅技术结合的设计方案。在发送电路中,先进行AGM低功耗编码,再采用一种基于电荷分享的电容型低摆幅发送电路(CCS)将数据发送出去。AGM编码有效地降低数据的翻转率,CCS电路将电容预加重型技术和电荷分享型技术相结合,不但降低了数据翻转的摆幅,而且使得信号在“0→1”跳变时无需从VDD获取能量,从而使互连线动态功耗直接减半,同时该电路还继承了电容预加重型电路的高带宽优点。在接收电路中,利用AC耦合电阻反馈反相器(CRFI)将信号偏置在VDD/2附近,同时转换为RZ脉冲信号。最后通过迟滞比较器将信号还原为全摆幅信号,并通过AGM解码器还原数据信息。基于SMIC 65nm工艺,采用Cadence IC610软件对其进行仿真,结果表明,CCS电路和AGM编码结合的方式能够有效的降低互连线上的功耗,同时提高了其抑制串扰的能力。相比于不使用AGM编码的全摆幅电路,单独使用AGM编码和CCS低摆幅电路在降低功耗方面分别为40%和72%左右,而采用AGM编码和CCS低摆幅电路结合的方式,其功耗下降了82%左右。同时由于数据抑制串扰能力的提高,数据最大传输速率进一步提高。
[Abstract]:Network on-chip (NoC) is a new communication method for multi-processor system on-chip (MPSoC). The system architecture based on network communication not only improves the communication efficiency, but also improves the expansibility. At the same time, the introduction of on-chip network effectively solves the problems of global synchronization, bandwidth limitation and power consumption in traditional bus SoC. However, with the gradual development of integrated circuit technology, especially after entering deep sub-micron process, non-ideal effects such as crosstalk caused by interconnection structure in NOC have brought a series of problems such as power consumption, delay and reliability. Therefore, how to design high-speed and low-power NoC interconnection structure has become one of the hot topics in the field of on-chip network design. In order to solve the power problem of interconnection in NoC, a novel low power encoding with crosstalk suppression capability is proposed. The low power part of the coding adopts the improved GM code based on the low power self-calibration code (SCG). At the same time, time coding technology is introduced to improve the ability of crosstalk suppression. A parallel serial / series-parallel conversion circuit is also added to the encoder and decoder architecture, which reduces the power consumption and saves the wiring resources by reducing the number of interconnects. The simulation results show that the power consumption of interconnect is reduced by 37.51 for 32bit random data source coding. In order to further reduce the interconnect power consumption of NoC, a design scheme combining low power coding and low swing technique is adopted. In the transmission circuit, AGM low power coding is performed first. Then, a kind of capacitive low swing transmission circuit based on charge sharing (CCS) is used to transmit the data. AGM code can effectively reduce the turnover rate of the data. The CCS circuit combines the capacitive preweighting technology with the charge sharing technology. Not only the swing of data flipping is reduced, but also the signal does not need to obtain energy from VDD during the "0 ~ 1" jump, thus the dynamic power consumption of the interconnect is reduced by half directly. At the same time, the circuit inherits the advantages of high bandwidth of capacitive preweighting circuit. In the receiving circuit, the AC coupling resistor feedback inverter (CRFI) is used to bias the signal near the VDD/2 and to convert the signal to the RZ pulse signal at the same time. Finally, the signal is restored to full swing signal by hysteresis comparator and data information is restored by AGM decoder. Based on SMIC 65nm technology, Cadence IC610 software is used to simulate it. The results show that the combination of CCS circuit and AGM coding can effectively reduce the power consumption on the interconnect and improve its ability to suppress crosstalk. Compared with the full swing circuit without AGM coding, the power consumption of AGM coding and CCS low swing circuit is about 40% and 72% respectively, while that of AGM coding and CCS low swing circuit is about 82%. At the same time, the maximum data transmission rate is further improved because of the improvement of the crosstalk suppression ability of data.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN402

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